So that textiles fulfil their purpose of use and have the desired properties with respect to feel, appearance and use behaviour, they are specially processed. Apart from obtaining the fiber, yarn and twist production and the fabric production, there are further methods that influence the textile properties.
For example, a greater stability or more volume in the thread-like material, an increase in the temperature-resistance, a dyeing, a water-repellent or fungicidal finish are necessary, to only mention a few examples, depending on the purpose of use.
These so-called finishing methods can be carried out in all the process stages; there are finishing methods for fibers, yarns/twists and fabrics. Some finishing methods can be integrated into the production or further processing process but others are in turn discontinuous.
Many of these finishing methods require a subsequent thermal setting, which is generally carried out in a steam atmosphere or under dry heat in order to permanently stabilise the desired properties. Generally, the setting process is called thermosetting in the textile industry but in carpet yarn production the synonym heat-set process is used.
For example, in the area of carpet yarn production there are so-called straight set yarns and frieze yarns.
In straight set yarn, the straight linear structure of the single yarns or the cabled yarns or twists are thermoset, which in cut-pile carpets leads to straight pile loops arranged next to one another.
A three-dimensional forming is overlaid on the yarn in a separate process for frieze yarns between the cabling process and the heat-set process. In this case, the yarn is three-dimensionally formed by bending/compression and this state is thermoset. The yarns in the finished carpeting are formed like a walking stick in the case of cut-pile carpeting. These carpets have a lively surface structure, which is non-sensitive to footprints. More than half of the cabled yarns or twists processed in cut loop tufted carpets worldwide are given a so-called frieze appearance or textured appearance in a thermo-mechanical process.
After the forming, the cabled yarns or twists are subjected to a subsequent thermosetting process. Owing to the successive heating and cooling, the yarn relaxes and can shrink and bulk depending on the type of material. A maximum bulk is generally desired and for this the thread has to run through the thermosetting mechanism free of tension, in particular free of tensile stress and compressive stress. Furthermore, the yarn twist is permanently stabilised or set thereby, which, in the later use of the yarns, leads to a substantially improved wear-resistance and durability of the carpets or carpeting produced therefrom.
In practice, these methods are carried out by individual units that are independent of one another.
A thread finishing system is described in German Patent Publication DE 198 25 905 A1. Depending on whether a crimped or uncrimped thread is to be produced, it runs through a corresponding alternative unit and is deposited on a conveyor belt. On the conveyor belt, the thread is finally fed to an air-conditioning chamber for thermosetting. As different units are used to produce crimped or uncrimped threads, an adapter arranged downstream of the delivery roller is disclosed, which reduces the assembly outlay to convert the finishing system.
According to German Patent Publication DE 198 25 905 A1, a so-called compression chamber is used in order to be able to produce crimped threads (in the textile branch the terms compressed, formed threads or threads with a frieze effect are used as synonyms). The compression chamber, apart from a channel inlet and a channel outlet, has a through-channel. A so-called retaining flap, which exerts a retaining force counter to the transporting direction of the threads to be compressed, is arranged at the channel outlet with a joint on the channel wall. The threads to be compressed, via the channel inlet, reach the through-channel and are braked here on the walls of the through-channel and by the retaining flap until the yarn plug is so large that the retaining force of the retaining flap is overcome and threads come to rest via a sliding face arranged downstream of the channel outlet on a conveyor belt. Following this, the threads are fed on a conveyor belt to a separate thermosetting mechanism.
If, on the other hand, non-crimped threads or straight set yarns or twists are to be produced, a so-called loop depositor is necessary for this. The loop depositor contains a hollow shaft, into which a depositing tube projects. Together with the hollow shaft, the depositing tube can be driven to traverse. The threads, which are fed by the delivery roller pair, arrive through an inlet tube in a through-channel and finally in the channel of the traversing depositing tube so the threads are deposited in the form of thread loops on a conveyor belt in order to thereafter run through a separate thermosetting mechanism. Ignoring the bending radii, non-crimped or straight set threads are referred to.
A method for thermally treating a running yarn and a twisting machine for carrying out the method are known from German Patent Publication DE 10 2006 040 065 A1. For this purpose, each workstation has a steam setting mechanism, which can be driven by saturated steam or hot steam and is used for setting the yarn drawn off from the twisting mechanism.
The inlet and outlet openings have thread sluices, which are used to seal the thread treating chamber toward the surroundings. Such thread sluices are important components of yarn treating chambers of this type as, on the one hand, during operation, an efficient seal has to be ensured by the yarn that is running through and, on the other hand, the friction of the yarn that is running through should be as small as possible. The guidance of the yarn through the device is achieved in each case by a delivery mechanism arranged upstream of the device and one arranged downstream of the device. For this purpose, the two delivery mechanisms of the respective workstation are activated in such a way that the yarn running through the device runs through substantially tension-free. The yarn is wound onto a bobbin directly after leaving the treatment device.
The drawback in the method and the device is, however, that to set an effect, this individual unit has to be arranged downstream of another unit, which, for example, produces a frieze effect, so a relatively large installation space is required.
German Patent Publication DE 10 2007 014 556 A1, according to the title, discloses a combination of a method for producing frieze yarn with a cabling or twisting machine or integration of this method in a cabling and twisting machine connected to a heat-set unit. For this purpose, the textile yarn is firstly subjected to the cabling or twisting process, then the frieze effect is produced and thereafter the textile yarn thus formed is set in the heat-set unit. The device for frieze production may be arranged here in front of the heat-set mechanism or integrated in the heat-set mechanism. All the three method steps are to be combined in one machine.
Further specific design features are not contained in this publication.
The drawback in the method is that the proposed rigid integration of all the units in one machine reduces the flexibility of this procedure as exclusively yarn with a frieze effect can be produced using this cabling or twisting machine. In addition, high setting temperatures prevail in the compression chamber of the frieze unit and the heat-set unit if the frieze mechanism is integrated in the heat-set mechanism. However, if the setting temperature already acts during the compression of the thread on the retaining flap of the compression chamber, pressure points of the crossing thread layers, which are caused by the compression are produced and are also set. These pressure points impair the uniformity of the yarn, which, for example during dyeing, and therefore in the later fabric, leads to a non-uniform fabric appearance.
Furthermore, only a restricted bulking of the yarn, which is necessary to increase the volume, can be produced in this manner.